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  • Category: Science and Technology

    Why does LED bulb use less energy than CFL and filament type?

    Have a query about the amount of energy used by various types of light bulbs? Looking out for the scientific reasons for this information? Check out this page for advice from experts.

    With the advancement of technology first CFL has replaced the ordinary filament type bulb and now LED bulb is now replacing CFL type bulb.
    What makes LED a more effective and gives similar results compared to CFL and conventional filament type bulb?
    Why does LED bulb use less energy than CFL and filament type?
  • Answers

    7 Answers found.
  • Compact Fluorescent Lamp (CFL) is widely popular lighting system in India. These bulbs or tubes contain mercury (in the form of vapor) inside the bulb/tube, an inert gas (majorly Argon) and the surface of the bulb is coated with phosphorous (ex: tube lights). So when electricity passes between the cathode and anode inside the bulb, a chemical reaction is induced and produces ultraviolet light and heat. The color of the light changes depending on the inert gas inside the bulb. To produce different colors of the spectrum, many CFL bulbs are filled with different inert gases in different proportions to produce required colors. The Light produced by CFL bulbs have a longer wavelength. If you are familiar with wavelength and energy, you might know that energy and wavelength are inversely proportional. Hence the energy efficiency of CFL bulbs is very less compared to LED.

    Light Emission Diodes or LED's produce light without the intervention of a chemical reaction or need of any gas or mercury vapor. LED's have semiconductors which produce light when electrons travel from anode to cathode. The name itself indicates that it is a diode which emits light when electricity passes through it. Since the electrons move constantly the emitting diodes will emit light with an average lifespan of 50,000 hours. LED's emit light in shorter wavelength and thus are more energy efficient.

    Since there is no need of a complex chemical reaction, LED's use less energy (as it is based on the movement of electrons), more energy efficient and do not heat up as traditional CFL bulbs do. 80% of the energy of CFL is dissipated as heat. LED does not give similar results to CFL, in fact, it gives greater and better results. Though LED's are little pricey when compared to CFL, the annual energy savings and considering the replacement savings are much higher when you consider a long-term period. You may require replacing CFL very frequently and their energy consumption is also very high, but LED's power consumption is less and you need not replace them as frequently as you do with CFL.

    Thank You
    Dr. V. Shashikanth

  • LED light don't require more electricity to do its job of emitting light. It gets heated up quickly and illuminates the areas whereas CFL lights use more energy to get heated up. CFL light is also dangerous to the environment and paves way for Global Warming. LED Lights use about 50% less energy compared to CFL Lights.These days due to government initiative luckily the prices of LED Light have come down and is in reach of every common man

  • The first replacement for the regular incandescent bulb is the compact fluorescent bulb. But today in the market the best available bulb is the light emitting diode(LED) bulb.

    If you compare the efficiency of these bulbs a 12.5 watt LED bulb will give equivalent light to that of a 20 Watt CFL bulb. A Led bulb will have more life than CFL bulb, LED bulbs to contain no mercury whereas CFL bulb of 20-watt capacity will have about 5mg of mercury. As there is a chemical reaction involved in CFL the bulbs will get heated up very fast and a lot of energy will be wasted in this process. Similarly, carbon dioxide emissions will be very less in LED bulbs when compared to that of CFL bulbs.
    Because of the above facts, a LED bulb will be having the following benefits,
    1. More age.
    2. Less waste generation as bulbs will not fuse of fast.
    3. No mercury hence less hazardous.
    4. Less carbon footprint as CO2 emitted is less.
    5. Very less risk of fire
    6. The solid-state technology is used in making these bulbs. Hence less breakage.
    7. Less power consumption. A 12.5 Watt LED bulb consumes about 110KWH/Year electricity whereas a 20 Watt CFL bulb consumes around 175 KWH/Year. As less consumption of power, electricity bill will be less.
    But some people say that initial cost is more but if you see the power bill and replacement frequency you can recover the extra cost in a very short time period.

    The main reasons for less power consumption are.
    1. No chemical or chemical reaction is involved.
    2. No wastage of power in the heating up of the bulb

    always confident

  • Traditional filament bulb or CFL or LED lights are basically doing the job of converting electrical energy to light. Depending on their theory of operation and design they have different efficiencies of these conversions.

    In the traditional filament type bulbs, there is an enormous loss of electrical energy in heating the filament and only a small part of it is given out in form of light.

    In CFL due to gas ionization and more emission of light in the visible region, the efficiency is better and for the same light output less current is utilized which means less expense of electricity.

    LED are semiconductor devices which are most efficient as regards to the conversion of electric currents to output light. They work on the principle of electroluminescence. These semiconductor devices use very small currents but give light in better proportion in comparison to the earlier filament type or CFL.

    Just to understand the difference in their efficiencies let us see the efficiencies of the above three modes of light production using electrical energy : -
    For traditional filament bulbs - about 15 lumens/watt, for CFL - about 65 lumens/watt and for LED - about 100 lumens/watt.

    Knowledge is power.

  • The LED bulbs produces far more light per watt and produces much less heat. CFL bulbs take long time to warm up to full brightness. Both bulbs have a similar globe design and similar wide angles of 250-270 degrees. LED bulbs use only 2-17 watts of electricity and it does not contain mercury like CFL bulbs do, but contains other harmful components like lead and nickel. Over 95% of LED bulb is recycable. LED is the very cost effective because they use only the fraction of the electricity of traditional lighting methods and can last far longer. LED chips need controlled direct current electrical power and an appropriate circuit as an LED driver is required to convert the alternating current from the power supply to the regulated voltage direct current used by LEDs.

  • Actually in traditional bulb or in CFL Bulb the basic theory is same. There is certain type of inert gas, mercury vapour in them. In case of CFL bulb there is an inner coat of any chemical compound. Which is the cause behind different colors of CFL bulb.
    In case of these types of bulbs the electrical energy transforms into light. When you on the switch the current flows and the light illuminates your room.
    In case of LED bulbs there is small light emitting diode which USD for Illumination. Now when you compare between two of them, the LED bulbs are more efficient than CFL bulb. Because CFL bulbs emits dangerous chemicals and carbon dioxide when illuminates. It also causes global warming. but LED bulbs does not have such problem. Moreover LED bulbs consumes 50 percent less energy than CFL. So if there is a question of saving energy you must use LED instead of CFL or conventional bulb.

  • Over the years we started with having the standard tungsten or incadesence light blub followed by compact fluroscents (CFL) and now we have Light emitting diodes (LED).

    1. What makes LED a more effective and gives similar results compared to CFL and conventional filament type bulb?

    LED is preferred because it does not have mercury like that of CFL and much lower carbon dioxide emissions. It can handle minor physical impact better than conventional filament (which breaks) and also the CFLs(the glass breaks).

    The repeated swithcing on and switching off of the CFL and the filament blub reduces the life span but this has no impact on the LED bulb.The life span of LEDs is far better than the other two, THe LED life is roughly 7 times more than the CFL and arond 40 times more than the filamnet bulb.

    It uses less electricity when compared to filament (10 times more) and the CFL (2 times more).

    The regular filament bulbs get hot after some time, this is better with the CFL but the LED has the least amount of heat given out(1/10 th of the CFL and 1/25th of the filament bulb).

    So, these are the key points that makes LED better than the other two. THE CFL is not popular becaue it takes time to come to full power and is not enviornmental friendly.

    2. Why does LED bulb use less energy than CFL and filament type?

    The LED bulbs are an entirely different technology, basically a semi-conductor referred to as diode is designed, when electricity is passed through this, it emits a light. This is referred to as 'electro-luminescence'. This can be done at a low voltage compared to the other two types. hence the amount of lumens ( light) emitted/ watt(current) used by LED is better than CFL and the filament bulb. The technology of the LED is so superior that some believe that we should not compare the filament bulbs with LED.

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